Video processor, video processing method, integrated circuit for video processing, video playback device

ABSTRACT

A video processing apparatus acquires audio-visual environment information that indicates an audio-visual environment of a viewer that views video. The audio-visual environment information includes information of a display size of the video that is being viewed, information of brightness around a display apparatus that displays the video, and information of a distance between the viewer and the display apparatus. The video processing apparatus corrects, depending on information indicated by the audio-visual environment information, a basic reduction amount to reduce a quantity of motion of the video that is being played back, and processes the video with use of a corrected reduction amount. In the case where the display size is large, in the case where it is dark around, or in the case where the distance from the viewer to the display apparatus is short, the reduction amount to reduce a motion is set to be large.

TECHNICAL FIELD

The present invention relates to a video processing apparatus, a videoplayback apparatus, and in particular to a technique for preventingvisually induced motion sickness that occurs while a susceptible vieweris watching video.

BACKGROUND ART

In recent years, due to progress in technologies such as a small-sized,densely-packed component or the like, an imaging apparatus such as amovie camera has reduced in size and weight. At the same time, a highmagnification lens mounted on such a camera enables to shoot moreprecise images.

However, a small-sized apparatus having such a high magnification lensis likely to cause blurring during shooting video.

Therefore, a digital camera and a movie camera having a function forreducing such blurring have been popular, and there are various kinds offunctions for image stabilization.

For example, image-stabilizing system by using full digital processingdetects a motion between images that are output with use of a CCD(Charge Coupled Device). The system outputs an image stored in a feedmemory by moderating a motion vector of the detected motion in ahorizontal range and a vertical range.

Also, a lens shift-type image stabilizer includes plural lenses in itslens barrel. The plural lenses include a correction lens in a form of aninertia pendulum which also has a biaxial operation mechanism. The useof such a correction lens eliminates blurring generated by a handmotion.

In addition, an image stabilization function with a large-area imagesensor uses an image sensor that is larger than a normal effectivedisplay range (display size). The image stabilization function detects amotion with use of an acceleration sensor or the like and controls aread-out start position of pixels whose size are equivalent to thedisplay size in the image sensor, based on a signal output by theacceleration sensor.

Also, there is a method for correcting blurring not on an imagingapparatus but on a playback apparatus. An image-stabilizing by usingdigital processing function on the playback apparatus detects a motionfrom a playback image of video output. After a read-out position of theimage is determined in accordance with a motion vector of the image, theimage-stabilizing by using digital processing function reads andcontrols a read-out start position of the image that has beenaccumulated in a feed memory.

Patent Literature 1 discloses a method of image-stabilizing by usingdigital processing on the playback apparatus. Blurring is appropriatelysuppressed in accordance with an overscan amount of a television towhich a playback apparatus is connected.

CITATION LIST Patent Literature

-   [Patent Literature 1]-   Japanese Patent Application Publication No. H7-143338

SUMMARY OF INVENTION Technical Problem

In recent years, due to a spread of large-sized television sets at a lowprice, opportunities to view video on a large screen are increasing,compared to the past. In such a case, unfortunately, the video viewed onthe large screen are likely to cause a symptom that is so called“visually induced motion sickness” to viewers.

A configuration described in the above-mentioned Patent Literature 1 canminimize a degree of image deterioration that is caused by blurring,depending on an overscan amount. That is, while the configuration of thePatent Literature 1 can output highly accurate images, it is impossibleto prevent visually induced motion sickness suffered by viewers.

The present invention has been achieved in view of the above problem,and an aim thereof is to provide a video processing apparatus and avideo playback apparatus, each of which can reduce visually inducedmotion sickness suffered by viewers.

Solution to Problem

In order to solve the above problems, a video processing apparatus thatprocesses a video and outputs the processed video for playback, thevideo processing apparatus comprises: a motion information acquisitionunit operable to acquire motion information related to a motion betweentwo or more frames constituting the video; an audio-visual environmentinformation acquisition unit operable to acquire audio-visualenvironment information indicating an audio-visual environment of aviewer that views the processed video; a reduction amount output unitoperable to output, based on the audio-visual environment informationacquired by the audio-visual environment information acquisition unit, areduction amount for reducing a quantity of motion that is determined bythe motion information acquired by the motion information acquisitionunit; and a processing unit operable to process the video using thereduction amount output by the reduction amount output unit.

Also, A video processing method that processes a video played back by avideo playback apparatus, the video processing method comprises a stepof: acquiring motion information related to a motion between two or moreframes constituting the video; acquiring audio-visual environmentinformation indicating an audio-visual environment of a viewer thatviews the processed video; outputting, based on the audio-visualenvironment information acquired by the audio-visual environmentinformation acquisition unit, a reduction amount for reducing a quantityof motion that is determined by the motion information acquired by themotion information acquisition unit; and processing the video using thereduction amount output by the reduction amount output unit.

Also, A video processing integrated circuit that processes a video andoutputs the processed video for playback, the video processingintegrated circuit comprises: a motion information acquisition unitoperable to acquire motion information related to a motion between twoor more frames constituting the video; an audio-visual environmentinformation acquisition unit operable to acquire audio-visualenvironment information indicating an audio-visual environment of aviewer that views the processed video; a reduction amount output unitoperable to output, based on the audio-visual environment informationacquired by the audio-visual environment information acquisition unit, areduction amount for reducing a quantity of motion that is determined bythe motion information acquired by the motion information acquisitionunit; and a processing unit operable to process the video using thereduction amount output by the reduction amount output unit.

Also, A video playback apparatus that processes a video and outputs theprocessed video for playback, the video playback apparatus comprises: amotion information acquisition unit operable to acquire motioninformation related to a motion between two or more frames constitutingthe video; an audio-visual environment information acquisition unitoperable to acquire audio-visual environment information indicating anaudio-visual environment of a viewer that views the processed video; areduction amount output unit operable to output, based on theaudio-visual environment information acquired by the audio-visualenvironment information acquisition unit, a reduction amount forreducing a quantity of motion that is determined by the motioninformation acquired by the motion information acquisition unit; and aprocessing unit operable to process the video using the reduction amountoutput by the reduction amount output unit.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the above configuration, it is possible to process thevideo depending on the audio-visual environment of the viewer that viewsthe processed video, and it is therefore possible to prevent a visuallyinduced motion sickness of the viewer.

Also, the reduction amount output unit may output, as the reductionamount, an adjusted reduction amount that is obtained by adjusting apredetermined basic reduction amount using a correction amount that isdetermined based on the audio-visual environment information.

By determining the basic reduction amount, a correction depending on thebasic reduction amount is possible. Therefore, for example, by changingthe basic reduction amount depending on likelihood of motion sickness ofthe viewer, it is possible to determine a reduction amount depending onthe likelihood of motion sickness of the viewer.

Also, the audio-visual environment information may include sizeinformation indicating a size of a video display area of a displayapparatus that is to play back the processed video, and the reductionamount output unit may adjust the basic reduction amount based on thesize information.

Also, the reduction amount output unit may perform the adjustment byincreasing the basic reduction amount in proportion to the size of thevideo display area indicated by the size information.

Accordingly, the video processing apparatus can perform a correctiondepending on the display size of the video. As the display size of thevideo grows larger, the viewer is more likely to suffer from visuallyinduced motion sickness. Therefore, such a correction can preventvisually induced motion sickness of the viewer.

Also, when the size of the video display area indicated by the sizeinformation is larger than a predetermined size, the reduction amountoutput unit may perform the adjustment by increasing the basic reductionamount.

When the display size of the video exceeds the predetermined size,visually induced motion sickness is specifically likely to occur.Therefore, with use of a simple judgment mechanism that judges whetherthe display size of the video exceeds a predetermined threshold value,the video processing unit can perform a correction depending on thedisplay size of the video.

Also, the reduction amount output unit may perform the adjustment suchthat as the size of the video display area indicated by the sizeinformation grows larger, a vertical component of a vector that definesthe quantity of motion increases at a greater ratio than a horizontalcomponent of the vector.

Accordingly, as the display size of the video grows larger, a horizontalcorrection amount of the vector that defines the quantity of motion canbe increased at a greater ratio than a vertical correction amount of thevector. Since a motion in a vertical direction more greatly involvesvisually induced motion sickness than a motion in a horizontal directiondoes, such an adjustment can respond to such an involvement.

Also, the audio-visual environment information may include brightnessinformation indicate indicating brightness around a display apparatusthat is to play back the processed video, and the reduction amountoutput unit may adjust the basic reduction amount based on thebrightness information.

Also, the reduction amount output unit may perform the adjustment byincreasing the basic reduction amount in inverse proportion to thebrightness indicated by the brightness information.

Accordingly, the video processing apparatus can perform a correctiondepending on the brightness around. As it grows darker, the viewer ismore likely to suffer from visually induced motion sickness. Therefore,such an adjustment can prevent motion sickness of the viewer.

Also, when the brightness indicated by the brightness information islower than brightness indicated by a predetermined threshold value, thereduction amount output unit may perform the adjustment by increasingthe basic reduction amount.

When the brightness becomes lower than the predetermined brightness,motion sickness is specifically likely to occur. Therefore, with use ofa simple judgment mechanism that judges whether the brightness aroundthe display apparatus exceeds the predetermined threshold value, thevideo processing unit can perform a correction depending on thebrightness.

Also, the reduction amount output unit may perform the adjustment,regarding a horizontal component and a vertical component of a vectorthat defines the quantity of motion, such that the reduction amount ofthe vertical component is larger than the reduction amount of thehorizontal component.

Accordingly, as it grows darker, the horizontal correction amount of thevector that defines the quantity of motion can be increased at a greaterratio than the vertical correction amount of the vector. Since themotion in the vertical direction more greatly involves motion sicknessthan the motion in the horizontal direction does, such an adjustment canrespond to such an involvement.

Also, the audio-visual environment information may include viewerposition information indicating a distance between the viewer that viewsthe processed video and a display apparatus that is to play back theprocessed video, and the reduction amount output unit may perform theadjustment based on the viewer position information.

Also, the reduction amount output unit may perform the adjustment byincreasing the basic reduction amount in inverse proportion to thedistance indicated by the viewer position information.

Accordingly, the video processing apparatus can perform a correctiondepending on a viewer position. As the distance between the viewer andthe display apparatus that is to display the video grows shorter, motionsickness is more likely to occur. Therefore, such an adjustment canprevent motion sickness of the viewer.

Also, when the distance indicated by the viewer position information isshorter than a distance indicated by a predetermined threshold value,the reduction amount output unit may perform the adjustment byincreasing the basic reduction amount.

When the distance between the viewer and the display apparatus isshorter than the predetermined distance, motion sickness is specificallylikely to occur. Therefore, with use of a simple judgment mechanism thatjudges whether the distance between the viewer and the display apparatusexceeds the predetermined threshold value, the video processing unit canperform a correction depending on the distance between the viewer andthe display apparatus.

Also, the reduction amount output unit may perform the adjustment suchthat as the distance indicated by the viewer position information growsshorter, the reduction amount of a vertical component of a vector thatdefines the quantity of motion increases at a greater ratio than thereduction amount of a horizontal component of the vector.

Accordingly, as the distance grows shorter, the horizontal correctionamount of the vector that defines the quantity of motion can beincreased at a greater ratio than the vertical correction amount of thevector. Since the motion in the vertical direction more greatly involvesmotion sickness than the motion in the horizontal direction does, suchan adjustment can respond to such an involvement.

Also, the basic reduction amount may be composed of a vertical basicreduction amount and a horizontal basic reduction amount, and thevertical basic reduction amount may be larger than the horizontal basicreduction amount.

Accordingly, the vertical component of the vector can be reduced morethan the horizontal component of the vector. As a result, motionsickness becomes less likely to occur. This is because blurring in thevertical direction is more likely to cause motion sickness than blurringin the horizontal direction.

Also, the video processing apparatus may further comprises: an outputunit operable to, when the video that is stored in a recording medium isoverscanned, cut out and output a cut-out region determined based on thequantity of motion that is reduced in accordance with the adjustedreduction amount.

Accordingly, the video processing apparatus corrects the reductionamount, and outputs video data that has been cut out in accordance withthe overscan cut-out region based on the quantity of motion determinedby a corrected reduction amount. Therefore, the viewer that views thevideo data is less likely to suffer from motion sickness.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a system diagram showing a usage pattern of a playbackapparatus.

FIG. 2 is a functional block diagram showing a function configuration ofthe playback apparatus.

FIG. 3 is a functional block diagram showing a function configuration ofa display apparatus.

FIG. 4 is a functional block diagram showing a function configuration ofan imaging apparatus.

FIG. 5 is a functional block diagram showing a function configuration ofthe video processing apparatus in the playback apparatus.

FIG. 6 is a functional block diagram showing a function configurationaccording to blur correction in the imaging apparatus.

FIG. 7 is a flowchart showing an example of a procedure of motionreduction process.

FIG. 8 is a flowchart calculating an adjustment amount of a reductionamount to reduce a quantity of motion of an image based on size ofdisplay area.

FIG. 9 is a flowchart calculating an adjustment amount of a reductionamount to reduce a quantity of motion of an image based on brightness.

FIG. 10 is a flowchart calculating an adjustment amount of a reductionamount to reduce a quantity of motion of an image based on position of aviewer.

FIG. 11 is an explanation showing a processing example of a quantity ofmotion.

DESCRIPTION OF EMBODIMENTS

The following describes a video processing apparatus according to anembodiment of the present invention and a playback apparatus on whichthe video processing apparatus is mounted with reference to thedrawings.

FIG. 1 is a system diagram showing a usage pattern of a playbackapparatus 100.

The playback apparatus 100 is typified by a BD (Blu-ray Disc) player ora DVD (Digital Versatile Disc) player, for example. The playbackapparatus 100 plays back a video stored on a recording medium such as aBD-ROM or a DVD-ROM, and a video received via the broadcast wave. Thevideo playback apparatus 100 is connected to a display apparatus 200 andan imaging apparatus 300 via an HDMI cable or the like.

The display apparatus 200 is, for example, typified by a digitaltelevision. Also, the imaging apparatus 300 is, for example, a digitalmovie camera. Video shot by the imaging apparatus 300 are stored in arecording medium disc 400. The recording medium disc 400 is insertedinto a drive of the playback apparatus 100 so as to be played back.

The playback apparatus 100 corrects a motion of video indicated by apiece of video data read from the recording medium disc 400, based onaudio-visual environment information (display size, brightness or thelike) of a viewer acquired by the display apparatus 200. Such video dataafter correction is output to the display apparatus 200. In thisdescription, the correction will be called blur correction. Blurcorrection is so called image stabilization in other words.

FIG. 2 is a functional block diagram showing a function configuration ofthe playback apparatus 100.

As FIG. 2 shows, the playback apparatus 100 includes a CPU (CentralProcessing Unit) 101, a memory 102, an HDMI (High-Definition MultimediaInterface) 103, a network communication unit 104, a disc drive 105, adecoder 106 and a video processor 107. The compositional elements of theplayback apparatus 100 is connected with one another via an internal bus108.

The CPU 101 controls each compositional element of the playbackapparatus 100. Especially, when a video is played back, the CPU 101determines a reduction amount for reducing a quantity of motion betweenframes of a video for playback. The CPU 101 acquires, from the displayapparatus 200, audio-visual environment information indicatingaudio-visual environments (display size of the video for playback,ambient brightness and distance from a display to a viewer) of a viewer.The audio-visual environments may be called viewing environments. TheCPU 101 then obtains, based on the acquired audio-visual environmentinformation, a correction amount of the reduction amount with regard toeach of audio-visual environments. Each correction amount is adjusted bybeing added to a basic reduction amount. An adjusted reduction amount isoutput to the video processor 107 via the internal bus 208.

The memory 102 stores therein various programs and data that arenecessary to operate the playback apparatus 100, and includes a ROM(Read Only Memory) and RAM (Random Access Memory). The ROM storestherein various execution programs and data to define operations of theCPU 101. The ROM includes a recording medium and a nonvolatile memorysuch as a flash ROM that is writable and capable of holding storedcontents even when the power is off. The RAM includes a volatile memoryincapable of holding stored contents when the power is off.

The HDMI 103 is a connection interface to a HDMI cable. The HDMI 103transmits/receives data to/from the display apparatus 200 via the HDMIcable. For example, the HDMI 103 outputs a video signal to the displayapparatus 200.

The network communication unit 104 is a connection interface to anetwork communication channel which connects to, via a LAN cable. Thenetwork communication unit 104 transmits/receives data to/from thedisplay apparatus 200.

The recording medium disc 400 is inserted in the drive 105. Inaccordance with an instruction issued by the CPU 101, the drive 105reads data from the recording medium disc 400, and outputs the readdata. Also, the drive 105 writes data that has been output from the CPU101 into the recording medium disc 400.

The decoder 106 decodes video data that is to be played back, andoutputs the decoded video data.

The video processor 107 receives the video data decoded by the decoder106, and performs a process on the received data to reduce a motion ofthe video.

FIG. 3 is a functional block diagram showing a function configuration ofthe display apparatus 200.

As FIG. 3 shows, the display apparatus 200 includes a CPU 201, a memory202, a sensor 203, a display 204, an HDMI 205, and a networkcommunication unit 206. The compositional elements of the displayapparatus 200 is connected with one another via an internal bus 207.

The CPU 201 controls each part of the display apparatus 200. Inaddition, when video is being played back, the CPU 201 obtains a displaysize of the video with use of a monitor size (information on the displaysize in inches) and a display mode (full-screen playback, or reducedvideo playback (in the case where a reduction rate is ½, each of heightand width of the display is multiplied by 0.5, in the case where areduction rate is ¼, each of height and width of the display ismultiplied by 0.25, or the like)) of the display apparatus 200. The CPU201 successively also transmits the obtained display size to theplayback apparatus 100 via the HDMI 205 or the network communicationunit 206.

The memory 202 stores therein various programs and data that arenecessary to operate the display apparatus 200, and includes a ROM and aRAM. The ROM stores therein various execution programs and data todefine operations of the CPU 201. The ROM includes a recording mediumand a nonvolatile memory such as a flash ROM that is writable andcapable of holding stored contents even when the power is off. The RAMincludes a volatile memory incapable of holding stored contents when thepower is off.

The sensor 203 measures brightness of an audio-visual environment or aviewer position, and includes a brightness sensor, an ultrasonic sensorand the like. According to the present embodiment, the brightness sensormeasures brightness around the display apparatus 200, and the ultrasonicsensor measures a distance between the display apparatus 200 and aviewer, with use of ultrasonic reflection. The sensor 203 transmits themeasured brightness as brightness information and the distance betweenthe display apparatus 200 and the viewer as viewer position informationto the playback apparatus 100 via the HDMI 205 or the networkcommunication unit 206.

The display 204 is an apparatus for displaying video, and is for examplea LCD (Liquid Crystal Display).

The HDMI 205 is a connection interface to an HDMI cable. The HDMI 205receives a video signal from the playback apparatus 100.

The network communication unit 206 is a connection interface to anetwork communication channel which connects to, via a LAN cable. Thenetwork communication unit 206 transmits/receives data to/from theplayback apparatus 100.

FIG. 4 is a functional block diagram showing a function configuration ofthe imaging apparatus 300.

As FIG. 4 shows, the imaging apparatus includes a CPU 301, a memory 302,an acceleration sensor 303, a drive 304, a decoder 305, an encoder 306and a camera unit 307. The compositional elements of the imagingapparatus 300 is connected with one another via an internal bus 308.

The CPU 301 controls each element of the imaging apparatus 300.

The memory 302 stores therein various programs and data that are neededto operate the imaging apparatus 300, and includes a ROM and a RAM. TheROM stores therein various execution programs and data to defineoperations of the CPU 301. Examples of the ROM include a nonvolatilememory or a recording medium such as a flash ROM. Such a memory iswritable, and capable of holding stored contents even when the power isoff. Examples of the RAM include a volatile memory incapable of holdingstored contents when the power is off.

The acceleration sensor 303 measures an acceleration value of a motionof the camera unit 307, and outputs the measured acceleration value tothe internal bus 308.

The recording medium disc 400 is inserted in the drive 304. Inaccordance with an instruction issued by the CPU 101, the drive 304reads data from the recording medium disc 400, and outputs the readdata. Also, the drive 304 writes data that has been output from the CPU301 into the recording medium disc 400. The video data stored on therecording medium disc 400 has been encoded by the encoder 306.

The decoder 305 decodes video data to be played back, and outputs thedecoded video data, when the imaging apparatus plays back the video datastored in the memory 302 or the recording medium disc 400.

The encoder 306 encodes video data stored in the memory 302, and outputsthe video data after encoding.

The camera unit 307 includes a lens, a CCD and the like. The camera unit307 performs an imaging process, and stores imaged video data in thememory 302.

FIG. 5 is a functional block diagram showing function sections thatperform video processing in the playback apparatus 100.

A video processing unit 500 includes an acquisition unit 510, anaudio-visual environment information storage unit 520, a motioninformation detection unit 530, a reduction amount output unit 570, anda motion reduction processing unit 580. The acquisition unit 510, themotion information detection unit 530 and the reduction amount outputunit 570 are realized by a software process performed by the CPU 101.The motion reduction processing unit 580 is realized by the videoprocessor 107.

The acquisition unit 510 successively acquires audio-visual environmentinformation from the display apparatus 200 with use of a CEC (ConsumerElectronics Control) function of the HDMI 103 or the networkcommunication unit 104, and stores the acquired audio-visual environmentinformation in the audio-visual environment information storage unit520.

The audio-visual environment information storage unit 520 stores thereindisplay area size information 521, brightness information 522 and viewerposition information 523, as audio-visual environment information usedas an indicator of motion sickness of a viewer.

The display area size information 521 includes information of a displaysize of a video that is displayed on the display apparatus 200, andinformation of a display position in the case where a video is playedback in a reduced display mode. The information of the display size isdetermined by multiplying the display size of the display apparatus 200by a playback size of the video (full-screen playback, reduced videoplayback or the like) (by 1 in the case of full-screen playback, and bymultiplying factor according to a reduction size in the case of reducedvideo playback, for example, by 0.5 in the case of ½ reductionplayback). In the case of viewing a high-definition video with hi-visionresolution on a large display, a viewer is likely to suffer from motionsickness. Therefore, the video is corrected with use of the display areasize information 521.

The brightness information 522 is acquired by measuring brightnessaround the display apparatus 200. When a viewer views video in a darkplace, the viewer is likely to suffer from motion sickness. Therefore,the video is corrected with use of the brightness information 522.

The viewer position information 523 indicates a distance from a viewerto the display apparatus 200. When the distance from the viewer to ascreen that displays a video is short, the viewer is likely to sufferfrom motion sickness. Therefore, the video is corrected with use of theviewer position information 523.

The motion information detection unit 530 detects a quantity of motionbetween frames of video data stored in a storage unit 540, and outputsthe detected quantity of motion to the motion reduction processing unit580. The quantity of motion corresponds to a change amount of anoverscan cutout region between the frames, with respect to the decodedvideo data. The overscan cutout region is a region that is cut out dueto overscan. Besides, in the case where the recording medium disc 400has also stored therein blur information while imaging, the blurinformation corresponds to the quantity of motion. Accordingly, in sucha case, the motion information detection unit 530 outputs the blurinformation as the quantity of motion. Also, in the case where a motionvector in MPEG code is attached to the video data as appendixinformation, the motion information detection unit 530 outputs themotion vector as the quantity of motion. In addition, in the case wherethe quantity of motion is detected by analyzing video frame data, themotion information detection unit 530 performs a matching arithmeticoperation between a previous field image and a current field image, anddetects the quantity of motion within one field by acquiring adifference between those field images.

The reduction amount output unit 570 acquires each piece of audio-visualenvironment information from the audio-visual environment informationstorage unit 520. Based on each piece of the audio-visual environmentinformation, the reduction amount output unit 570 determines acorrection amount of an adjustment amount of a reduction amount, andnotifies the motion reduction processing unit 580 of the correctionamount. The reduction amount output unit 570 has stored therein areference value (also referred to as basic reduction amount) thatindicates beforehand how much the quantity of motion is to be reduced,and outputs, to the motion reduction processing unit 580, a correctionamount (also referred to as adjustment reduction amount) that isobtained by using the determined correction amount to the basicreduction amount.

The motion reduction processing unit 580 acquires the correction amountof the adjustment amount of the reduction amount from the reductionamount output unit 570. The motion reduction processing unit 580generates a video whose quantity of motion acquired from the motioninformation detection unit 530 is adjusted with use of the correctionamount, and stores the video in video buffer 560.

The storage unit 540 corresponds to the recording medium disc 400, andstores therein video data to be played back and appendix information.Besides, in some cases, the imaging apparatus 300 has already performeda blur reduction process on the stored video data in the storage unit540. In such a case, the storage unit 540 may store therein blurinformation detected in the imaging apparatus 300 and reduced blurinformation together with corresponding video data. Besides, theappendix information is management information related to thecorresponding video data, meta information and the like.

A video playback unit 550 corresponds to the decoder 106. The videoplayback unit 550 decodes the video data stored in the storage unit 540,and stores the decoded video data in the video buffer 560.

The video buffer 560 corresponds to the memory 102. The video buffer 560stores therein the video data decoded by the video playback unit 550.

A video output unit 590 acquires the decoded video data or a processedvideo data that has been processed for reducing a motion throughout thevideo, and outputs such video data as a video signal. The video outputunit 590 is a process performed in the CPU 101, and outputs the videodata to the display apparatus 200 via the HDMI terminal.

FIG. 6 is a functional block diagram showing a function configurationaccording to a video processing unit 600 that performs a videoprocessing in the imaging apparatus 300. According to the presentembodiment, the video processing unit 600 shown in the figure isrealized by a software process by the CPU 301.

As FIG. 6 shows, the video processing unit 600 includes an imaging unit610, a blur reducing unit 620, a blur information detection unit 630, avideo buffer 640, a video coding unit 650, a reduced blur informationrecording unit 660, a video recording unit 670, a blur informationrecording unit 680 and a storage unit 690.

The imaging unit 610 corresponds to the camera unit 307. The imagingunit 610 stores an imaged video in the video buffer 640.

The blur information detection unit 630 corresponds to the accelerationsensor 303. The blur information detection unit 630 detects a motion ofthe video imaged by the imaging unit 610, and notifies the blur reducingunit 620 of a direction and an amount of detected blurring, as blurinformation.

The blur reducing unit 620 corresponds to a process performed in the CPU301. The blur reducing unit 620 corrects blurring by adjusting a readposition from a CCD of the camera unit 307 or a read/write position ofthe video buffer, controlling the camera unit 307 or the like. Besides,a basic blur correction technology is a conventional art, and thereforea detailed explanation is omitted.

The image buffer 640 corresponds to the memory 305. The image buffer 640temporarily stores therein the video data imaged by the imaging unit610.

The video coding unit 650 corresponds to the encoder 306. The videocoding unit 650 encodes the video data stored in the image buffer 640,and outputs the encoded data into the video recording unit 670.

The video recording unit 670 is a process performed in the CPU 301. Thevideo recording unit 670 receives the data encoded by the video codingunit 650, and stores the data in the storage unit 690.

The blur information recording unit 680 is a process performed in theCPU 301. The blur information recording unit 680 receives the blurinformation detected by the blur information detection unit 630, andstores the blur information in the storage unit 690.

The reduced blur information recording unit 660 is a process performedin the CPU 301. When a blur correction is performed at the time ofimaging, the reduced blur information recording unit 660 receivesreduced blur information corrected by the blur reducing unit 620, andstores the reduced blur information in the storage unit 690.

The storage unit 690 stores the blur information detected by the blurinformation detection unit 630 and the blur information reduced by theblur reducing unit 620 in the recording medium disc 400 together with anencoded video. In addition, these pieces of information are stored as atable of time and motion vectors in time series. Besides, regarding theblur information and the reduced blur information, the table of time andmotion vectors may be stored in a different file from the video data, orstored so as to be embedded into the video data (for example, into TSpacket).

From the configuration above, the imaging apparatus 300 can provide theplayback apparatus 100 with the blur information and the reduced blurinformation at the time of imaging together with the video data, withuse of the storage medium disc 400.

<Operation>

Next, the following explains an operation of an imaging apparatus and avideo processing apparatus according to the present embodiment with useof flowcharts shown in FIGS. 7-10.

First, here is an explanation of a whole flow of a video processing perunit time, with use of the flowchart shown in FIG. 7. After that, therewill be explanation of a method for determining a correction amount thatcorrects a reduction amount using each piece of audio-visual environmentinformation is explained, with use of the flowcharts shown in FIGS.8-10.

FIG. 7 is a flowchart showing the video processing per unit time. Byoperating the playback apparatus 100 in accordance with the flowchart,the video processing is performed. That is, a quantity of motion isreduced. An operation shown in the flowchart of FIG. 7 is successivelyperformed while a video is played back, and the processing is performedon next video data that is to be played back next to the video that iscurrently being played back or video data that is to be played backafter the next video data.

The video playback unit 550 starts the processing and decodes the videodata that is to be played back that is stored in the storage unit 540,and the decoded video data is stored in the video buffer 560. Inaddition, the acquiring unit 510 successively acquires audio-visualenvironment information of a viewer from the playback apparatus 200, andthe audio-visual environment information storage unit 520 stores thereineach piece of audio-visual environment information based on a currentaudio-visual environment.

The motion information detection unit 530 detects motion informationrelated to a quantity of motion of each frame by analyzing the videodata and appendix information of the video data stored in the storageunit 540, or analyzing video frame data developed in the video buffer560. In the case of analyzing the video data, the motion informationdetection unit 530 reads motion vector data included in MPEG code. Inthe case of analyzing the video frame data developed in the video buffer560, the motion information detection unit 530 performs a matchingarithmetic operation between a previous field image and a current fieldimage, and detects a quantity of motion within one field by acquiring adifference between those field images.

Besides, motion sickness is known to occur mainly when an input fromthree semicircular canals of a human is greatly different from an inputfrom vision. Especially, a motion that is likely to cause motionsickness is relatively a low frequency motion between 0.1 Hz and 3 Hz,and slower than one field ( 1/60 second). For this reason, it isnecessary not only to calculate the above mentioned quantity of motionof each frame but also to measure a quantity of motion throughout 20-120frames.

The quantity of motion throughout 20-120 frames can be measured bymaintaining frame data a predetermined time before (for example, onesecond before) and detecting a quantity of motion between a videocorresponding to the maintained frame data and a video that is to beplayed back. Also, the quantity of motion may be measured by causing thevideo buffer 560 to maintain 20-120 frames, or with use of a processingmethod such as panning detection and tilting detection.

Also, in the case of using the motion vector data in the MPEG code, thequantity of motion may be measured by maintaining not only the motionvector data of each frame but also a sum of motion vectors for a pastpredetermined time period (for example, one second).

The motion information detection unit 530 included in the playbackapparatus 100 acquires the quantity of motion per unit time (forexample, per 10 frames) (Step S701).

The reduction amount output unit 570 acquires a basic reduction amount(Step S702). The basic reduction amount is a base of each of a verticalbasic reduction amount and a horizontal basic reduction amount. Thesebasic reduction amounts has been stored beforehand in a memory.

Also, the reduction amount output unit 570 acquires the display areasize information 521 from the audio-visual environment informationstorage unit 520. After that, the reduction amount output unit 570calculates a correction amount for correcting the basic reduction amountthat is based on the display area size information 521 (Step S703). Adetail of how to calculate the correction amount will be described laterwith use of the flowchart shown in FIG. 8.

Next, the reduction amount output unit 570 acquires the brightnessinformation 522 from the audio-visual environment information storageunit 520. After that, the reduction amount output unit 570 calculates acorrection amount for correcting the basic reduction amount that isbased on the brightness information 522 (Step S704). A detail of how tocalculate the correction amount will be described later with use of theflowchart shown in FIG. 9.

After that, the reduction amount output unit 570 acquires the viewerposition information 523 from the audio-visual environment informationstorage unit 520. After that, the reduction amount output unit 570calculates a correction amount for correcting the basic reduction amountthat is based on the viewer position information 523 (Step S705). Adetail of how to calculate the correction amount will be described laterwith use of the flowchart shown in FIG. 10.

The reduction amount output unit 570 outputs an adjusted reductionamount to the motion reduction processing unit 580 (Step S706). Theadjusted reduction amount is obtained by using the correction amountobtained by adding each of correction amounts acquired from Step S703 toStep S705.

The motion reduction processing unit 580 determines an overscan cutoutregion that is to be cut out after the processing, based on the adjustedreduction amount. The motion reduction processing unit 580 thentransmits the determination regarding the overscan cutout region to thevideo buffer 560.

The video playback unit 550 decodes the video data stored in the storageunit 540, and writes the decoded video data into the video buffer 560 inaccordance with a time axis of a video.

The video buffer 560 cuts out the decoded video data in accordance withthe overscan cutout region transmitted by the motion reductionprocessing unit 580. Center of the overscan cutout region is at the endof the quantity of motion indicated by a processed quantity of motion.The video buffer 560 then outputs the cut out video data to the videooutput unit 590.

The video output unit 590 outputs the video data output by the videobuffer 560 to the display apparatus 200 via the HDMI 103. The displayapparatus 200 displays the video based on the output video data (StepS707). By this processing, the quantity of motion is corrected based onthe audio-visual environment information of the viewer, and accordinglythe display apparatus 200 displays the video that is less likely tocause motion sickness.

Assume that a display size of the video is larger than a threshold valueS2, brightness is higher than a threshold value L1 and lower than athreshold value L2, and a distance between a viewer and the displayapparatus 200 is less than a threshold value D1. In this case, thecorrection amount of the reduction amount is calculated as follows:+30%+10%−10%=30%. Also, assume that a reference value of the verticalreduction amount is 60% and a reference value of the horizontalreduction amount is 40%. In this case, the vertical corrected reductionamount is 90% (60%+30%=90%), the horizontal corrected reduction amountis 70% (40%+30%=70%), and a processed quantity of motion is obtained asfollows: a vertical component of the motion vector that defines aquantity of motion detected by the motion information detection unit 530is multiplied by 0.9 and a horizontal component of the motion vector ismultiplied by 0.7. With use of the processed quantity of motion as thequantity of motion, the decoded video is cut out in accordance with theoverscan cutout region and output. In addition, the processed quantityof motion is never in an opposite direction from a direction indicatedby the quantity of motion before the processing. That is, the reductionamount neither exceeds 100% nor becomes minus.

The above described is an operation from the acquisition of thereduction amount of the quantity of motion, through the videoprocessing, to the output of the video.

FIG. 8 is a flowchart for calculating the adjustment amount of thereduction amount for reducing the quantity of motion of the video basedon the display area size, and shows a content of the processingperformed in Step S703 above.

The reduction amount output unit 570 acquires the display area sizeinformation 521 from the audio-visual environment information storageunit 520. The reduction amount output unit 570 judges whether thedisplay area size in accordance with the display area size information521 is larger than a threshold value S1 (Step S801).

In the case where the display area size is smaller than the thresholdvalue S1 (YES in Step S801), the reduction amount output unit 570determines “−10%” for the correction amount based on the display areasize (Step S801), and ends the process.

In the case where the display area size is larger than the thresholdvalue S1 (NO in Step S801), the reduction amount output unit 570 thenjudges whether the display area size is smaller than the threshold valueS2 (S2>S1) (Step S802).

In the case where the display area size is larger than the thresholdvalue S1 and smaller than the threshold value S2 (YES in Step S802), thereduction amount output unit 570 determines “+20%” for the correctionamount based on the display area size (Step S804), and ends theprocessing.

In the case where the display area size is larger than the thresholdvalue S1 and not smaller than the threshold value S2, that is, thedisplay area size is larger than S2 (NO in Step S802), the reductionamount output unit 570 determines “+30%” for the correction amount basedon the display area size (Step S803), and ends the processing.

The above described is a specific content of the processing performed inStep S703 in the flowchart shown in FIG. 7. Additionally, in thisflowchart, when the display area size is smaller than the thresholdvalue S1, the correction amount is reduced (determined as −10%). Becausein this case, a viewer is less likely to suffer from motion sickness,prevention of image deterioration due to a reduction of the quantity ofmotion takes priority. That is, there is a tradeoff between preventionof motion sickness and prevention of image deterioration. Accordinglysuch a processing is performed.

FIG. 9 is a flowchart for calculating the adjustment amount of thereduction amount for reducing the quantity of motion of video based onbrightness, and shows a content of the processing performed in Step S704above.

The reduction amount output unit 570 acquires the brightness information522 from the audio-visual environment information storage unit 520. Thereduction amount output unit 570 judges whether brightness in accordancewith the brightness information 521 is higher than the threshold valueL1 (Step S901).

In the case where the brightness is lower than the threshold value L1(YES in Step S901), the reduction amount output unit 570 determines“+30%” for the correction amount based on the brightness (Step S905),and ends the processing.

In the case where the brightness is higher than the threshold value L1(NO in Step S901), the reduction amount output unit 570 then judgeswhether the brightness is lower than a threshold value L2 (L2>L1) (StepS902).

In the case where the brightness is higher than the threshold value L1and lower than the threshold value L2 (YES in Step S902), the reductionamount output unit 570 determines “+10%” for the correction amount basedon the brightness (Step S904), and ends the processing.

In the case where the brightness is higher than the threshold value L1and not lower than the threshold value L2, that is, the brightness ishigher than L2, (NO in Step L902), the reduction amount output unit 570determines “−10%” for the correction amount based on the brightness(Step S903), and ends the processing.

The above described is a specific content of the processing in Step S704in the flowchart shown in FIG. 7. Besides, the correction amount isreduced in Step S905 because of the same reason explained above in thecase of FIG. 8.

FIG. 10 is a flowchart for calculating the adjustment amount of thereduction amount for reducing the quantity of motion of video based on adistance between the viewer and the display apparatus 200, and shows acontent of the processing in Step S705 above.

The reduction amount output unit 570 acquires the viewer positioninformation 523 from the audio-visual environment information storageunit 520. The reduction amount output unit 570 judges whether thedistance in accordance with the viewer position information 523 islonger than the threshold value D1 (Step S1001).

In the case where the distance is shorter than the threshold value D1(YES in Step S1001), the reduction amount output unit 570 determines“+30%” for the correction amount based on the distance (Step S1001), andends the processing.

In the case where the distance is longer than the threshold value D1 (NOin Step S1001), the reduction amount output unit 570 determines “−10%”for the correction amount based on the distance (Step S1002), and endsthe processing.

The above described is a specific content of the processing in Step S705in the flowchart shown in FIG. 7. Besides, the correction amount isreduced in Step S1002 because of the same reason explained above in thecase of FIG. 8.

The video playback apparatus 100 determines a final adjusted reductionamount for adjusting the quantity of motion by adding the basicreduction amount to the correction amounts acquired by the processingsin FIGS. 8-10. The playback apparatus 100 determines a cutout regionbased on the quantity of motion that has been reduced in accordance withthe final adjusted reduction amount, cuts out the video in accordancewith the cutout region, and outputs the cutout video to the displayapparatus 200.

<Example of Motion Reduction Processing>

The following describes, with use of FIG. 11, an example of a case wherethe motion reduction processing unit 580 performs a motion reductionprocessing in accordance with flowcharts shown in FIGS. 7-10.

Regarding a decoded video 1100 that is decoded video data, the motionreduction processing unit 580 calculates a vertical component 1107 and ahorizontal component 1109 of a motion vector 1106 that indicates thequantity of motion detected by the motion information detection unit530.

The motion reduction processing unit 580 calculates a vertical componentfor reduction 1108 of the motion vector, by multiplying the calculatedvertical component 1107 by a vertical reduction amount output by thereduction amount output unit 570.

In the same manner, the motion reduction processing unit 580 calculatesa horizontal component for reduction 1110 of the motion vector, bymultiplying the calculated horizontal component 1109 by the horizontalreduction amount output from the reduction amount output unit 570.

That is, a motion vector for reduction 1104 in FIG. 11 shows a quantityof motion that is to be reduced.

The motion reduction processing unit 580 performs an overscan processingby performing a cut-out processing (cut-out in accordance with anoverscan cut-out region 1102) such that a position 1111 becomes acenter. The position 1111 is shifted from a central position 1101 of thedecoded video 1100 by a distance indicated by the motion vector forreduction 1104. By this shift, the original decoded video 1100 is movedin an opposite direction of the motion vector for reduction 1104, andthen displayed. That is, the motion vector for reduction 1104 is reducedfrom the original motion vector 1106, and the motion of the decodedvideo 1100 is reduced. Besides, at this time, a magnification processingis also performed due to the overscan processing. However, theexplanation of the magnification process is omitted since themagnification process is only a simple calculation and has beenperformed conventionally.

Also, in the case where the video is continuously moving in onedirection, not only a simple processing for reducing a motion but alsoanother processing is performed, for example, reducing a compensationamount of a start and an end of the motion, like a processing such aspanning detection and tilting detection in blur correction.

As described above, the video is displayed after an overscan processingis performed based on the motion vector for reduction 1104. Therefore,motion sickness of the viewer can be reduced.

CONCLUSION

As described in the embodiment above, the playback apparatus 100corrects and the video based on the audio-visual environment of theviewer that views the video acquired from the display apparatus 200, andplays back the corrected video. Therefore, the playback apparatus 100can reduce motion sickness suffered by the viewer as much as possible,while image deterioration is being reduced to the necessary minimum. Thecorrection can be made according to the environment of the viewer, andtherefore it is possible to provide a playback apparatus that is moreuser-friendly than ever before.

A video imaged by a general user with use of a camera-integratedrecording apparatus that is recordable with hi-vision resolution islikely to cause motion sickness compared to commercial contents forbroadcast or distribution, since, for example, the user is not used tothe camera and cannot image the video stably. Also, in recent years, ahigh-quality large flat screen television is becoming cheap, andaccordingly more accessible. However, a viewer is likely to suffer frommotion sickness when the viewer views a high-quality video on a largescreen such as a flat screen television. The playback apparatusdescribed in the embodiment is especially effective in the case wheresuch a video imaged by the general user is viewed on the large screen.

<Supplementary>

While the present invention has been described with reference to thepreferred embodiment, it is obviously understood that the presentinvention is not limited thereto. Hereinafter, various modificationswill be explained. Such modifications are included in the presentinvention other than the embodiment described above.

(1) The above embodiment has been explained by giving examples such asthe display area size information 521, the brightness information 522and the viewer position information 523 as audio-visual environmentinformation. However, the audio-visual environment information may beany information that indicates a viewer's audio-visual environment thatrelates to motion sickness, and the correction amount may be obtainedwith use of information other than the information described in theabove embodiment.

For example, in the case of displaying different groups of videos, thequantity of motion of each group is different from one another. Thismakes a viewer likely to suffer from motion sickness. Therefore, whiledisplaying the groups of the videos, the number of the groups may beused as the audio-visual environment information. Also, the correctionamount may be determined depending on whether the number of the groupsdisplayed on the display apparatus 200 is plural. That is, in the caseof displaying the groups of the videos, the quantity of motion may becorrected by determining the correction amount of the reduction amountas, for example, “+20%”, and in the case of displaying a single group ofthe video, the quantity of motion may be corrected by determining thecorrection amount of the reduction amount as, for example, “0”.Naturally, the correction amount may be changed depending on thresholdvalues that are based on the number of the groups of the videos.

Also, as the audio-visual environment information, information ofbrightness of irradiation by a light source of the display apparatus200, that is so called a backlight, may be used for determining thecorrection amount. In such a case, preferably, the correction amountincreases in proportion to a level of the irradiation by the backlight.

(2) According to the embodiment above, the video imaged by a moviecamera that is the imaging apparatus 300 is written into the recordingmedium disc 400. After that, the video that have been stored in the discis read, and played back after the quantity of motion is corrected.However, video data that is to be played back may not be read from thedisc. The video data may be directly transmitted to the playbackapparatus 100 from a HDD built in the imaging apparatus 300, byconnecting directly the imaging apparatus 300 to the playback apparatus100, with use of a USB cable, for example.

That is, any method may acquire a video that is to processed by thevideo processing apparatus according to the present invention. Forexample, video data may be acquired from streaming distribution.

(3) According to the embodiment above, when the correction amount of themotion reduction amount is determined, the final adjusted reductionamount is calculated by adding the basic reduction amount to thecorrection amount obtained from each of audio-visual environmentinformation.

However, a method for calculating the adjusted reduction amount does nothave to use a method described above. For example, the adjustedreduction amount may be obtained by multiplying the basic reductionamount by the correction amount obtained from each piece of audio-visualenvironment information. Besides, preferably, depending on each method,an appropriate correction amount is simulated and then determined.

(4) According to the embodiment above, the display apparatus 200includes sensors 203. However, since the sensors 203 are provided so asto acquire information related to the audio-visual environmentinformation of a viewer, the sensors 203 may be external equipments ifthe sensors can acquire the audio-visual environment information of theviewer. Also, the sensors may be included not in the display apparatus200 but in the playback apparatus 100. In a usage pattern as FIG. 1shows, even if the sensors 203 are included in the playback apparatus100, the approximately same measurement result can be obtained when thesensors 203 are included in the display apparatus 200.

Also, the display apparatus 200 may be not a normal display but aprojecting apparatus such as a projector. In such a case, the viewerposition information indicates a distance from a projector to a screen.That is because a viewer views a video projected by the projector at avicinity of the projector. Besides, in such a case, the viewer positioninformation may be determined by measuring a distance from the projectorto the screen with use of focusing accuracy of the projector, withoutincluding sensors.

Also, the display apparatus 200 may be a HMD (Head Mount Display). Insuch a case, a virtual distance calculated from a focal position in avirtual screen on the HMD may be used as the viewer positioninformation. Also, some HMDs completely shut light of outside. Thebrightness information in such a case is determined with use ofbrightness of a part that does not display the video.

(5) According to the embodiment above, the sensors 203 included in thedisplay apparatus 200 regularly output the brightness information or theviewer position information. However, if the playback apparatus 100 canacquire the audio-visual environment information, any configuration maybe used. For example, the playback apparatus 100 may require theaudio-visual environment information of the display apparatus 200, andthe display apparatus 200 may transmit the audio-visual environmentinformation to the playback apparatus based on the requirement.(6) According to the embodiment above, threshold values for determiningthe correction amount of the motion reduction amount are storedbeforehand in the playback apparatus 100. However, the number of thesethreshold values is not limited to the number of levels described in theembodiment above, and may be divided into any levels. For example,according to the embodiment above, two threshold values of the displayarea size are provided. However, the number of these values may be fiveor only one, for example.

Similarly, the correction amount of the motion reduction amountdescribed in the embodiment above is one example. As FIGS. 8-10 show,the correction amount only has to be an amount for preventing motionsickness in accordance with the audio-visual environment information.

Also, without including threshold values, the playback apparatus maystore therein a relational expression that defines each piece ofaudio-visual environment information and the correction amount withrespect to a value indicated by each piece of audio-visual environmentinformation, and the correction amount may be determined based on therelational expression. In such a case, the relational expression is asfollows: the correction amount of the reduction amount increases inproportion to the display area size; the correction amount of thereduction amount increases in proportion to the brightness; and thecorrection amount of the reduction amount increases in inverseproportion to the distance between the viewer and the display apparatus.

Furthermore, the playback apparatus 100 may include a configuration forchanging the correction amount according to a user input. For example,the playback apparatus 100 may have a configuration that provides aparameter for likelihood of motion sickness such that a viewer can setwhether the viewer is likely to suffer from motion sickness. In such aconfiguration, in the case where a viewer who is likely to suffer frommotion sickness views the video, the correction amount of the motionreduction amount may be large, and in the case where a viewer who is notlikely to suffer from motion sickness views the video, the correctionamount of the motion reduction amount may be small, compared to the caseof the viewer who is likely to suffer from motion sickness.

(7) According to the embodiment above, the HDMI cable and itsinput/output terminal are described. However, they may be any cable thatcan be used for input/output of the video, and they may be cables suchas a composite cable, an S terminal cable, a component cable and a Dterminal cable and an input/output terminal corresponding to thosecables.

Similarly, regarding a network connection, according to the embodimentabove, connection with use of a LAN cable is described as an example.However, connection with use of an Ethernet terminal and its cable,connection such as a wireless LAN, Bluetooth or the like may be used.

(8) The CPU according to the embodiment above may be composed of one CPUor plural CPUs.(9) According to the embodiment above, a LCD is described as one exampleof the display 204. However, the display 204 has only to display thevideo, and may be, for example, a PDP (Plasma Display Panel), a CRT(Cathode Ray Tube) display, an organic electroluminescence display andthe like.(10) According to the embodiment above, on the assumption that there isone viewer, a distance between the viewer and the display apparatus 200is measured so as to be determined as the viewer position information.However, in reality, plural viewers sometimes view the video.

In such a case, the sensors 203 of the display apparatus 200 may use theviewer position information of a viewer who is nearest to the displayapparatus 200. This is a measuring method that considers a problem thatas a distance to the display grows shorter, the viewer is likely tosuffer from motion sickness at a greater ratio.

Alternatively, the viewer position information may be an average valueof acquired distances between each of plural viewers and the displayapparatus.

(11) According to the embodiment above, the reduction amount in bothdirections, that is a vertical direction and a horizontal direction, isdetermined with use of only one reference. However, adjusted reductionamounts in the vertical direction and in the horizontal direction may beseparately determined, by using different flows for determining thereduction amount, such that the vertical correction amount differs fromthe horizontal correction amount.

That is, regarding the correction amount in each of flowcharts shown inFIGS. 8-10, the vertical correction amount may differ from thehorizontal correction amount. In such a case, considering that blurringin the vertical direction affects motion sickness suffered from a viewermore than blurring in the horizontal direction does, the verticalcorrection amount is preferably determined so as to be larger than thehorizontal correction amount.

For example, if FIG. 8 shows a flowchart for determining the horizontalcorrection amount, in another flowchart for determining the verticalcorrection amount, the correction amount in Step S803 shown in FIG. 8may be “+50%”, and the correction amount in Step S804 may be “+30%”.

Besides, in the case of a correction for reducing the reduction amount,that is, in Step S805 in FIG. 8, the vertical correction amount and thehorizontal correction amount may be the same.

(12) According to the embodiment above, the acquisition unit 510successively acquires the audio-visual environment information. However,for example, in the case of viewing a stationary digital television, onthe assumption that the audio-visual environment will not changelargely, the acquisition unit 510 may acquire the audio-visualenvironment information only once immediately before playing back thevideo, and may not successively acquire the audio-visual environmentinformation while the video is being played back.(13) According to the embodiment above, the video processing shown inFIG. 7 is successively performed while the video is being played back.However, if the audio-visual environment of a viewer does not change,all of the video data that is to be played back may be processed beforebeing played back, processed video data may be stored, and then thevideo may be played back.(14) The video processing unit 500 according to the embodiment above mayinclude some or all of function sections except for the video processingunit 500 in FIG. 5. The configuration may be realized by one dedicatedcircuit or an integrated circuit.(15) According to the embodiment above, the playback apparatus 100 orthe imaging apparatus 300 includes the drive 105, and reads or writesthe video data from the recording medium disc 400. However, the drivehas only to read a recording medium that stores therein the video data,and write the data into the recording medium. Also, the recording mediummay not be limited to a disc.

For example, in place of the drive, a USB memory interface may be used,and the recording medium disc may be a USB flash memory. Also, in placeof the drive, a card reader writer may be used, and the recording mediumdisc may be an SD memory card.

In addition, the playback apparatus 100 or the imaging apparatus 300 mayinclude not only one but a plurality of such interfaces for accessingthe recording medium.

(16) According to the embodiment above, the video processing unitperforms a reduction processing by a software processing, due to programexecution by the CPU.

However, each function section in the video processing unit may berealized by a dedicated circuit that performs operations shown in theflowcharts in FIGS. 7-10. The dedicated circuit may be integrated.

Similarly, each function section of the playback apparatus 100, thedisplay apparatus 200 and the imaging apparatus 300 may be integratedand realized by one or plural LSI (Large Scale Integration). Also,plural function sections may be realized by one LSI.

Note that although an LSI is used here, the circuit may be variouslydescribed as an IC (Integrated Circuit), a system LSI, a VLSI (VeryLarge Scale Integration), a SLSI (Super Large Scale Integration) or anULSI (Ultra Large Scale Integration) depending on the level ofintegration.

Note also that the technique used for the integration does not have tobe LSI. A special-purpose circuit or general-purpose processor may beused instead. LSI circuits whose configurations can be altered afterproduction such as the programmable FPGA (Field Programmable Gate Array)or a reconfigurable processor whose circuit cell connections andsettings are reconfigurable may also be used.

Moreover, if, due to progress in the field of semiconductor technologyor the derivation of another technology, a technology to replace LSIemerges, such a technology may be used to integrate the functionalblocks. The use of biotechnology or the like is considered to be apossibility.

(17) A control program composed of program code for making a processorsuch as a video playback apparatus or the like, and various circuitsconnected to the processor perform operations according to the preferredembodiment (see FIGS. 7-10), a video processing or the like may berecorded on a recording medium or distributed via various communicationpath (for example, telecommunications networks, wireless or wirednetwork, and network represented by internet). The recording medium maybe an IC card, a hard disc, an optical disc, a flexible disc, a ROM(read only memory), or the like. The distributed control program may beprovided for use by being stored in a memory or the like that isreadable by a processor in an apparatus, and the functions of the mobilecommunication terminal described in the preferred embodiment may berealized by the processor executing the control program.

INDUSTRIAL APPLICABILITY

The playback apparatus of the present invention can be used as anapparatus that is not likely to cause motion sickness while playing backa video imaged with use of a digital video camera or the like. Theplayback apparatus of the present invention can be used for an opticaldisc player such as a DVD player, a BD player, or a digital camera orthe like.

REFERENCE SIGNS LIST

-   -   100 playback apparatus    -   101 CPU (Central Processing Unit)    -   102 memory    -   103 HDMI (High-Definition Multimedia Interface)    -   104 network communication unit    -   105 disc drive    -   106 decoder    -   107 video processor    -   108 internal bus    -   200 display apparatus    -   201 CPU    -   202 memory    -   203 sensor    -   204 display    -   205 HDMI    -   206 network communication unit    -   207 internal bus    -   300 imaging apparatus    -   301 CPU    -   302 memory    -   303 acceleration sensor    -   304 drive    -   305 decoder    -   306 encoder    -   307 camera unit    -   308 internal bus    -   400 recording medium disc    -   500 video processing unit    -   510 acquisition unit    -   520 audio-visual environment information storage unit    -   521 display area size information    -   522 brightness information    -   523 viewer position information    -   530 motion information detection unit    -   540 storage unit    -   550 video playback unit    -   560 video buffer    -   570 reduction amount output unit    -   580 motion reduction processing unit    -   590 video output unit    -   600 video processing unit    -   610 imaging unit    -   620 blur reducing unit    -   630 blur information detection unit    -   640 video buffer    -   650 video coding unit    -   660 reduced blur information recording unit    -   670 video recording unit    -   680 blur information recording unit    -   690 storage unit

1. A video processing apparatus that processes a video and outputs theprocessed video for playback, the video processing apparatus comprising:a motion information acquisition unit operable to acquire motioninformation related to a motion between two or more frames constitutingthe video; an audio-visual environment information acquisition unitoperable to acquire audio-visual environment information indicating anaudio-visual environment of a viewer that views the processed video; areduction amount output unit operable to output, based on theaudio-visual environment information acquired by the audio-visualenvironment information acquisition unit, a reduction amount forreducing a quantity of motion that is determined by the motioninformation acquired by the motion information acquisition unit; and aprocessing unit operable to process the video using the reduction amountoutput by the reduction amount output unit.
 2. The video processingapparatus of claim 1, wherein the reduction amount output unit outputs,as the reduction amount, an adjusted reduction amount that is obtainedby adjusting a predetermined basic reduction amount using a correctionamount that is determined based on the audio-visual environmentinformation.
 3. The video processing apparatus of claim 2, wherein theaudio-visual environment information includes size informationindicating a size of a video display area of a display apparatus that isto play back the processed video, and the reduction amount output unitadjusts the basic reduction amount based on the size information.
 4. Thevideo processing apparatus of claim 3, wherein when the size of thevideo display area indicated by the size information is larger than apredetermined size, the reduction amount output unit performs theadjustment by increasing the basic reduction amount.
 5. The videoprocessing apparatus of claim 3, wherein the reduction amount outputunit performs the adjustment by increasing the basic reduction amount inproportion to the size of the video display area indicated by the sizeinformation.
 6. The video processing apparatus of claim 3, wherein thereduction amount output unit performs the adjustment such that as thesize of the video display area indicated by the size information growslarger, a vertical component of a vector that defines the quantity ofmotion increases at a greater ratio than a horizontal component of thevector.
 7. The video processing apparatus of claim 2, wherein theaudio-visual environment information includes brightness informationindicating brightness around a display apparatus that is to play backthe processed video, and the reduction amount output unit adjusts thebasic reduction amount based on the brightness information.
 8. The videoprocessing apparatus of claim 7, wherein when the brightness indicatedby the brightness information is lower than brightness indicated by apredetermined threshold value, the reduction amount output unit performsthe adjustment by increasing the basic reduction amount.
 9. The videoprocessing apparatus of claim 7, wherein the reduction amount outputunit performs the adjustment by increasing the basic reduction amount ininverse proportion to the brightness indicated by the brightnessinformation.
 10. The video processing apparatus of claim 7, wherein thereduction amount output unit performs the adjustment, regarding ahorizontal component and a vertical component of a vector that definesthe quantity of motion, such that the reduction amount of the verticalcomponent is larger than the reduction amount of the horizontalcomponent.
 11. The video processing apparatus of claim 2, wherein theaudio-visual environment information includes viewer positioninformation indicating a distance between the viewer that views theprocessed video and a display apparatus that is to play back theprocessed video, and the reduction amount output unit performs theadjustment based on the viewer position information.
 12. The videoprocessing apparatus of claim 11, wherein when the distance indicated bythe viewer position information is shorter than a distance indicated bya predetermined threshold value, the reduction amount output unitperforms the adjustment by increasing the basic reduction amount. 13.The video processing apparatus of claim 12, wherein the reduction amountoutput unit performs the adjustment by increasing the basic reductionamount in inverse proportion to the distance indicated by the viewerposition information.
 14. The video processing apparatus of claim 12,wherein the reduction amount output unit performs the adjustment suchthat as the distance indicated by the viewer position information growsshorter, the reduction amount of a vertical component of a vector thatdefines the quantity of motion increases at a greater ratio than thereduction amount of a horizontal component of the vector.
 15. The videoprocessing apparatus of claim 2, wherein the basic reduction amount iscomposed of a vertical basic reduction amount and a horizontal basicreduction amount, and the vertical basic reduction amount is larger thanthe horizontal basic reduction amount.
 16. The video processingapparatus of claim 2, further comprising: an output unit operable to,when the video that is stored in a recording medium is overscanned, cutout and output a cut-out region determined based on the quantity ofmotion that is reduced in accordance with the adjusted reduction amount.17. A video processing method that processes a video played back by avideo playback apparatus, the video processing method comprising a stepof: acquiring motion information related to a motion between two or moreframes constituting the video; acquiring audio-visual environmentinformation indicating an audio-visual environment of a viewer thatviews the processed video; outputting, based on the audio-visualenvironment information acquired by the audio-visual environmentinformation acquisition unit, a reduction amount for reducing a quantityof motion that is determined by the motion information acquired by themotion information acquisition unit; and processing the video using thereduction amount output by the reduction amount output unit.
 18. A videoprocessing integrated circuit that processes a video and outputs theprocessed video for playback, the video processing integrated circuitcomprising: a motion information acquisition unit operable to acquiremotion information related to a motion between two or more framesconstituting the video; an audio-visual environment informationacquisition unit operable to acquire audio-visual environmentinformation indicating an audio-visual environment of a viewer thatviews the processed video; a reduction amount output unit operable tooutput, based on the audio-visual environment information acquired bythe audio-visual environment information acquisition unit, a reductionamount for reducing a quantity of motion that is determined by themotion information acquired by the motion information acquisition unit;and a processing unit operable to process the video using the reductionamount output by the reduction amount output unit.
 19. A video playbackapparatus that processes a video and outputs the processed video forplayback, the video playback apparatus comprising: a motion informationacquisition unit operable to acquire motion information related to amotion between two or more frames constituting the video; anaudio-visual environment information acquisition unit operable toacquire audio-visual environment information indicating an audio-visualenvironment of a viewer that views the processed video; a reductionamount output unit operable to output, based on the audio-visualenvironment information acquired by the audio-visual environmentinformation acquisition unit, a reduction amount for reducing a quantityof motion that is determined by the motion information acquired by themotion information acquisition unit; and a processing unit operable toprocess the video using the reduction amount output by the reductionamount output unit.